let human = {
    name: "奉先",
    age: 35,
    friend: {
        name: "刘煜鑫",
        age: 20
    }
}

let human2 = {...human}; 
console.log("human2 =",human2); // { name: '奉先', age: 35, friend: { name: '刘煜鑫', age: 20 } }

// 使用对象的扩展运算符拷贝的属性，仍然是浅拷贝
human.friend.age = 21;
console.log(human2.friend.age); // 21